The present invention relates to a sealing plug for a multi-contact electrical connector which precludes the necessity for installation of separate end-seal plugs and spare pin contacts to effect the environmental sealing of non-used contact cavities.
The multi-contact electrical connector to which the sealing plug of the present invention is adapted to be applied is of the type disclosed in U.S. Pat. Nos. 3,970,352 and 4,639,061 wherein the connector includes a plug portion having a shell containing a dielectric plastic insert having pin contact receiving cavities extending therethrough. A relatively soft silicone rubber gasket is mounted in the shell at the forward end of the plug on one side of the plastic insert and provided with apertures aligned with the insert cavities. The gasket is provided with conical projections surrounding the apertures to afford a tight seal with the mating face of the receptacle portion of the connector.
A rear elastomeric grommet is mounted in the shell on the opposite side of the plastic insert and is provided with annular sealing ribs for making a sealing engagement with the insulated wire connected to a pin contact mounted in the insert and extending through the gasket apertures at the front of the plug portion of the connector and extending into a socket contact provided in the mating receptacle portion of the connector.
Heretofore, when sealing a non-used pin contact receiving cavity in the plug portion of the connector, it was customary to insert a spare pin contact into the dielectric insert and through the gasket, and to insert a separate end seal plug into the rear grommet. The spare pin contact was employed to stabilize or maintain the rigidity of the conical projections on the plug gasket to optimize the seal between the mated plug and receptacle portions of the connector. Furthermore, the spare pins provided a field-expedient capability where wiring changes were facilitated with the availability of spare pins for wire termination.
While the above-noted sealing arrangement was satisfactory for its intended purpose, certain disadvantages were experienced, notably, the spare pins became bent during connector usage, and in many instances, spare socket contacts were not installed in the receptacle portion of the connector due to their high cost; thereby eliminating the capability of making wire changes in the field.
After considerable research and experimentation, the sealing plug of the present invention has been devised which is constructed and arranged as a single unit or member to provide the functions of the heretofore employed end seal plug and spare pin contact, and comprises essentially a plastic plug having a length such that it extends through the rear grommet, the dielectric insert and gasket. The forward portion of the sealing plug extends a short distance outwardly from the gasket but not into the socket contact cavity of the mating receptacle portion of the connector, and the rear portion of the plug is engaged by the annular sealing ribs of the grommet, whereby the environmental sealing of the rear grommet and gasket protrusion is provided.
The sealing plug is designed to be installed, retained and extracted in the same manner as a spare pin contact; however, the shank portion of the plug extends outwardly beyond the rear grommet for gripping purposes and to provide a guide for applying an extraction tool when the plug is to be removed.